超臨界二氧化碳制備聚乳酸開孔微孔材料2-3ShiENCN

MicrocellularPLA-basedfoamswithopencellstructureandtailoredcellmorphologybybatchfoamingprocesswithsupercriticalCO2超臨界二氧化碳制備聚乳酸開孔微孔材料及其結(jié)構(gòu)調(diào)控研究2016Poly-FoamConferencePresenter:XuetaoShi,GuangchengZhang匯報人：史學(xué)濤，張廣成DepartmentofAppliedChemistry,NorthwesternPolytechnicalUniversity西北工業(yè)大學(xué)理學(xué)院應(yīng)用化學(xué)系2016年10月Outline匯報提綱1234Background背景介紹Preparation

ofPLAblends聚乳酸多相體系制備MicrocellularfoamingofPLAblends聚乳酸微孔發(fā)泡

Conclusion

結(jié)論2Background研究背景LacticacidLactide分子間氫鍵LifecycleApplication3PLABioplasticsDrugdeliveryTissue

EngineeringLandfillIncinerationCompostingBiomassBackground研究背景PLAforPackagingApplicationPLAintissueengineering4PLAasthemostwidelyusedbiopolymer聚乳酸是目前最常用的生物材料

Goodtransparency透光性Degradation降解性Biocompatibility生物相容性Processability優(yōu)異加工性NervousCardiovascularCutaneousMusculoskeletalPLAstereocomplex12PLAfiber3PLAfoamBackground研究背景5PLAFoaming聚乳酸發(fā)泡研究ChallengeLowmeltstrength低的熔體強度Application:Alternativeofpolystyrenefoamaspackaging,cushioning,construction,thermalandsoundinsulationmaterials.聚乳酸泡沫可作為聚苯乙烯泡沫的替代品廣泛用于包裝、建筑以及保溫隔音材料。

Application:PLAfoamsintissueengineeringwithoutstandingbiocompatibilityanddegradability聚乳酸泡沫因其優(yōu)異的生物相容性和可降解特性可應(yīng)用于組織工程領(lǐng)域。

Open-cellstructure開孔結(jié)構(gòu)StrategyMolecularweightandstructure聚合物結(jié)構(gòu)和分子量ChainextenderModifyingtheL/DratioconfigurationVaryingthePLA’smolecularweightCompoundingwithadditives和其他聚合物以及填料共混

Objective研究目標MicrocellularPLA-basedfoamswithopencellstructure聚乳酸開孔微孔材料

Tissueengineering組織工程6Enablecelladhesion,migration,proliferation滿足細胞黏附，遷移和增殖的要求Highporosity空隙率biocompatible,nontoxic,nonimmunogenic生物相容性，安全無毒，無免疫性Biopolymer生物材料BatchFoamingbySupercriticalCO2超臨界二氧化碳間歇發(fā)泡方法PLALDPEHDPEEVAABSPPPCEVOHTPOPHBPEOPCLPEGPBSPBATPEGPHBVPTATPVOHBiodegradable

PolymerBlends生物可降解聚合物共混PreparationofPLAblends聚乳酸共混體系制備Extrusionpelletization擠出造粒7Sheetextrusion片材擠出HaakePolylabOSsystem哈克單螺桿體系

PLA/PBAT(orPBS)聚乳酸共混體系PBAT聚對苯二甲酸丁二醇酯和己二酸丁二醇酯共聚物8PBS聚丁二酸丁二醇酯Fracture

surface

morphology(a)PLA/10%PBAT(b)PLA/10%PBSPhasemorphologyofPLA/PBSblendsPLAPLA/10%PBS9PLA/50%PBSPLA/30%PBSPLA/40%PBSViscoelasticpropertiesofthePLAblends流變性能10Angularfrequencydependenceof

η*(left)andG’(right)at180℃角頻率對復(fù)合黏度（左圖）和損耗模量（右圖）的影響

ThermalbehaviorofPLAblends多相體系熱性能11PLA/PBATblendsPLA/PBSblends

Tm-PBS(°C)Tg(°C)Tcc(°C)Tm-PLA(°C)ΔHc(J/g)ΔHm(J/g)X(%)PLA---59.3100.7166.231.8240.809.7PLA/10PBS110.357.591.1165.519.0445.9331.9PLA/20PBS111.757.784.6165.419.3243.7432.6PLA/30PBS112.854.995.6165.7---46.21---PLA/40PBS113.155.491.2165.7---43.42---PLA/50PBS113.354.594.5166.0---52.44---ExampleGaseousmass-transferbehavior氣體傳質(zhì)行為12SolubilityofCO2inPLAandPLAblendsat12MPaandat45°C超臨界二氧化碳在

聚乳酸及其共混物的飽和吸收（12MPa,45℃）PLA/PBATblendsPLA/PBSblendsSc-CO2hasahighersolubilityinthePLAmatrixcomparedtothatofPA66,PPandPC

超臨界二氧化碳在聚乳酸體系中有著較高的飽和吸收度Theequilibriumgasconcentrationdecreaseswiththeincreasingofthesecondphasecontent

二氧化碳飽和吸收度隨著聚乳酸多相體系中第二相含量的增大而降低Gaseousmass-transferbehavior氣體傳質(zhì)行為13Plotsofmeasureddesorptionweightfraction(Md)againstthesquarerootofdesorptiontime(td)GasdesorptionofPLA/PBATblendsCO2diffusedfollowedtheFickiandiffusionmechanisminashorttime,followedbyamoreslowlydecreasing二氧化碳在聚乳酸體系中的解吸附短時間遵循Fickian擴散機理，而后緩慢降低CO2contentsreachaplateauwithsolubilityofaround3gCO2/100gpolymer經(jīng)過長時間解吸附后聚乳酸體系中二氧化碳含量降至3gCO2/100gpolymer左右。SamplesDd(m2/s)PLA4.37E-12PBAT6.05E-12PLA/10PBAT2.15E-12PLA/10PBAT/5CaCO36.98E-13ThermalpropertiesofPLAsampleswithdifferentCO2content

不同二氧化碳含量下的聚乳酸體系熱性能對比14DSCheatingcurvesforPLAsamples(a)withoutCO2,(b)withsaturatedsc-CO2and(c)afterdesorptionfor12hours聚乳酸共混體系不同二氧化碳含量下的DSC曲線及其主要參數(shù)對比SamplesPLAPLA-10%PBATPLA-5%CaCO3PLA-10PBAT-5CaCO3Tga59595858b37404039c40454547Tcca102899999Texa154151154154Tma166165166166b168168170170c169169169169Xc

a9.6%20.4%17.4%15.3%b36.7%35.2%37.9%37.1%c33.8%32.6%37.6%35.1%Batchfoamingprocessing間歇發(fā)泡法15Sc-CO2saturationpressurewasfixedtobe12MPaat45℃

固定超臨界飽和條件為：壓力12MPa，溫度45℃Foamingtemperature:150℃,

160℃or170℃fortime(3s,6sor15s)

發(fā)泡溫度設(shè)定為150℃，160℃或170℃，發(fā)泡時間為3s，6s或15sFoamingafterCO2inthePLAsampledesorptionfordifferenttimes

二氧化碳飽和吸收的聚乳酸體系在解吸附一定時間后發(fā)泡FoammorphologyofPLAsystems聚乳酸體系微孔發(fā)泡16Influenceof

foamingtemperature150℃160℃170℃PLAPLA/10PBATPLA/10PBS50μm50μm50μm50μm50μm50μm50μm50μm50μmFoammorphologyofPLAsystems聚乳酸體系微孔發(fā)泡17Influenceof

foamingtime3s6s15sPLA160℃PLA/10PBAT160℃PLA/10PBS170℃50μm50μm50μm50μm50μm50μm50μm50μm50μmFoammorphologyofPLAsystems聚乳酸體系微孔發(fā)泡Cellgrowth12hours24hours36hours

PLAPLA-PBATPLA-CaCO3PLA-PBAT-CaCO318AveragecellsizeCelldensityInfluenceof

CO2contents(PLA/PBAT)FoammorphologyofPLAsystems聚乳酸體系微孔發(fā)泡PLA

PLA/PBS

12h24h36h19Influenceof

CO2contents(PLA/PBS)50μm50μm50μm50μm50μm50μmFoammorphologyofPLAsystems聚乳酸體系微孔發(fā)泡20Influenceof

CO2contentsabcdefghijklPLAPLA/10PBATPLA/10PBS0h12h24h36h12h24h36h50μm50μm50μm50μm50μm50μm10μm10μm10μm10μm10μm10μmFoammorphologyofPLAsystems聚乳酸體系微孔發(fā)泡

21FormationofopencellstructureabcdefPLA/PBATPLA/PBS5μm10μm10μm10μm10μm5μm21Conclusion

結(jié)論Sc-CO2hasarelativehighsolubilityinthePLAsystemsduetothecarbonylgroups超臨界二氧化碳在聚乳酸及其復(fù)合體系中有著較高的溶解度CO2diffusedfollowedtheFickiandiffusionmechanisminashorttime,thentheCO2contentsdecreasedmoreslowlytoaplateau

二氧化碳的解吸附過程在短時間內(nèi)遵循Fickian定律，而后經(jīng)長時間緩慢將至

3gCO2/100gpolymer.ThesecondphaseseparatedinthePLAmatrixasdomainsandtheformedinterfacebetweenPLAandthesecondphaseprovidestheheterogeneousnucleatingsites聚乳酸中的第二相在基體中以顆粒狀分散，由此形成的界面在發(fā)泡過程起到作為成核點的作用.22Conclusion

結(jié)論Thelowmeltstrengthandthetoughnessofsecondphasearethedominatedreasonfortheformationoftheopencellstructure.

第二相體系較低的熔體強度和其內(nèi)在韌性開孔結(jié)構(gòu)形成的主要原因。Themicrocellularmorphology